This is a basic science training grant focused on an integrative understanding of post- natal human behavioral development. The rationale for the focus on integrative training is that effective translation requires more than merely rapid movement of single-variable basic science findings to efficacy studies but a different basic science, one that embraces complex causal pathways of development, and considers processes at nested time scales and multiple levels of analysis. The training program focuses on behavioral development (and relations to brain development) because advancing research shows that post-natal behavior and experience modulates both structural and functional connectivity in the brain, tunes specialized neural systems and influences gene expression, with atypical patterns of early behavior and experiences determining the quality and opportunities of whole lifetimes. The trainees are 5 predoctoral candidates in psychology, cognitive science, and neuroscience and 3 postdoctoral fellows from various fields interested in developmental process. The training program for predoctoral trainees is 5 years (with 2 years supported by the training grant and 3 years by the participating PhD programs); the training program for postdoctoral trainees is typically 2 years. The training program emphasizes the use of cross-level methods to study the same problem, basic science that can link to translation, the collection and analysis of large data sets, open data and data sharing, and the ethical conduct of research.